Divided or partitioned drinking cups or other drinking vessels having multiple chambers for retaining liquid have long been known in the art. Typically, these drinking cups comprise a cup for a hot or a cold drink, which is split into chambers of roughly equal size by a number of fixed dividers originating radially from the center of the cup. The most common such cups will have two chambers of substantially equal size, separated by a divider running down the center of the cup.
Several different variants or purposes of multiple-chambered drinking cup are understood. Common varieties are dual-chambered plastic soft drink cups intended to allow a customer to be served two different flavors of soft drink, or dual-chambered drinking mugs intended to be used by two different people (such as a dating couple) at the same time.
However, existing drinking vessels with multiple chambers suffer from a number of downsides. First, because chambers are often of a fixed, narrow size, the drinking vessels can be difficult to clean. This inflexibility can also be user-unfriendly; because the chambers are of a fixed and usually equal size, a user of a multiple-chambered drinking vessel who wishes to fill it with multiple kinds of drink typically has little option but to fill the vessel with roughly equivalent amounts of each kind of drink, or to leave the vessel substantially underfilled. Second, existing multiple-chambered drinking vessels may have chambers of undesirable shape. In the vast majority of cases, the chambers of a multiple-chambered drinking vessel are formed side-by-side with each other, with each of the chambers contacting the edge of the drinking vessel. This can be undesirable from a heat transfer perspective, as particularly hot or cold drinks will tend to lose or gain heat from the surroundings of the cup despite the insulation that typically be present.